The present invention relates to a method of achieving high productivity improvement in automated manufacturing, and, in particular, relates to a method of increasing greatly an inspection workstation's throughput and data accuracy as related to items inspected.
Presently items such as printed wiring assemblies (PWA) having components thereon can be produced in an automated manner in great numbers. Although one would expect perfection in such a process, many defects do, indeed, occur to the dismay of all concerned. In order to reduce these defects of whatever nature, quality control personnel must first identify the defect. Obviously, if these boards are created in the thousands, or even in greater number, the inspection of each board becomes an almost inhuman task. In some places, boards can be randomly inspected or inspected at given intervals, such as every 10th or 100th board. An electronic tester may be used to identify a detective board, but a visual inspection may still be required if the defect is not in an identifiable component. Although this may not always be the case, every defective board may still be examined visually to determine the sources of error, if a visual one.
An inspector under the above conditions would identify the visual defect. This requires that he have volumes of reference material at hand to properly identify parts, etc. Once properly identified, this information must be manually recorded or perhaps even entered into a CRT type of terminal by hand by the inspector. This is very tedious taks, slows the throughput, and is even subject to error by the inspector himself thus compounding a quality control problem that once only existed on the board. If this information is manually recorded, it must further be typed onto computer cards or entered into a CRT type of terminal by a data entry clerk.
Obviously the chance for error in the above process is substantial. Further, the inspector is slowed in the process since he must use numerous references and record vast quantities of information.
These drawbacks have motivated a search for a method that minimizes the chance for error and further allows the inspector to substantially increase the number of items inspected per unit of time, the throughput rate.